Remove trailing whitespace
move gjoll_buf_t functions in buf.c
working on network API
cleanup gjoll.h and add some const
work on network API :

    - use uv_queue_work to call session_cb and parse/encrypt.
    - add void *data in session_t dans connection_t.
    - use gjoll_node_t to pass identifier.
    - call gjoll_preprocess_secret in gjoll_new_session.
clean network API and add recv_cb in daemon :

    - improve memory management : 0 leak
    - add receive callback in the daemon
Add service_id in gjoll_session_t.
Remove gjoll_service_t from gjoll_session_t :

because it's encrypted after create the session. So gjoll_service_t is given
in gjoll_recv_cb and gjoll_send.
big commit :

    - rename gjoll_buf_t.data to gjoll_buf_t.base (like uv_buf_t)
    - add encryption
    - update daemon
improve error gesture in network part
Cleanup code and fix memory alloc.
work on tests
Add gjoll_header_t in recv_cb and remove gjoll_service_t.
Update crypto.